Process of extracting metals from their ores.



W. A. SCHMIDT.

PROCESS OF EXTRACHNG METALS FROM THEIR GRES..

APPLICAUON FILED rE.1.19\5.

1 237,22 l Patented Aug. 14, 1917.

WALTER vAIiGrUsT SCHMIDT, OE LOS ANGELES, CALIFORNIA, ASSIGNOR To WESTERN PRECIPITATION COMPANY, OE Los ANGELES, CALIFORNIA, A CORPORATION OE CALIFORNIA, Y, f

To all 1'wlw/mi2? may, concern:

' `Be it known that l,V VAL'IER AUGUST Sciurinr, a citizen oft-lie United States, re

siding Aat Los Angeles, in the countyof Los Angeles and State of California, have invented a new and' useful Process for EX- 'tracting Metals from Their Ores, of which solutionwhichdissolves'the copper in the forni' offcopperclilorid. In such cases lit is i usual to provide'the leachwitha small perc-eiiitage of chlorin compound such as sodium chlorid or ofcalci'um chlorid so asto retain cupi'ous copper in solution. Mypr'ocess isparticularly applicable to treatment of ores containing an'alkaline*earth metalsuch as calcium, for example'in the form of calcite, and one Object of the present invention is to n utilizegjthe calcium clilorid formed in .the

leaching operation-as a carrier for thecuprous copper in solution, in such manner that only the clilorinconstituent need be supplied iii cyclicl Operation to maintain'th'e required amount of suclicarrier iii the solution. An- Otlier object of the linv'entioniis to provide'a pi'ocessof this kind in which all the chlorin used in5tli`e` operation is supplied in active form, as 'free cl'ilorin, thereby producing maximum effect 'for a given amount o clilorin" supplied. `Another l object of ,the invention is to so carry out the process that tlieloss of t-lilorin isreduced to a minimum. A further object of the, invention is to pro` vide for supplying the cliloi'in in such maiinei' tliattlie by-produ'cts obtained from the production of the'clilorin may wholly or partly pay the cost Of such production, so that unavoidable loss of chlorin in the tailings and ivasli water does not seriously affect the cost of the process;

The laccompanying drawing `is a side elevation of anapparatus suitable for carrying ont my invention. i The apparatus shown in the drawing comprises an agitator 1, nieans `for supplying. `finely divided ore thereto, means for receiving the material from the agitator and discharging it with as little loss of solution as .possible, an electrolytic cell, and means for supplying clilorin generated in said cell to the solution supplied tO the agitator.

The agitator 1 may be of any suitable or y TED sTAEs y PROCESS OEEXTRACTING METALS PROM THEIR ORES.

'Specification of Letters Patent. i Patented Auo- 14, 1917. Appiicationiiiea Pbruary 18,1916. seriali No. v79,100. i i i l trator or other means delivering the ore in a finely divided state along with considerable water. I prefer to provide means for dewatering the ore and replacing the water with a special replacing solution, for eX- ample, a solution' of vcalcium chlorid. The

ore is supplied by'lauiider 5 to a dewatering device 6 constructed forieXample as a Dorr classilieigzbe'ing provided with a tank 7 whose bottom inclines `upwardly toward the discharge end, so that a raking device 8, oper-v ated automatically in` the usual manner, may

draw the'vore over the discharge end., the

water being' largely left behind and runing over into an overflow Outlet 10. The oredischarges, from this device into a device 11 of similar` constructionto device 6, said device 11 discharging [into the agitator 1. A supply pipe 12 and an outlet pipel are provided for device 11, respectively for supply of displacing fluid to Saiddevice and for drawing Otf'such fluid. .v

u The Out-let pipe 15 of the agitator ldischarges into the first of a Series of devices 17, 18, 19 and20, each similar in construction to deviceA 6 land each discharging the ore into the succeeding device of the series, until the Ore lreaches the last device, from which it discharges by suitable means 21. T hel overlowfrom device 17 flows through pipe 22 to precipitating tank 23, from which a pipe 2l leads to the sump or barren solution tank 25. Tank 25 is preferably provided with twooutlet pipes 27 and 28. for conducting the barren solution respectively in two different cycles of circulation, namely a regenerating cycle through pipe 27 and the regenerating means hereinafter described and a displacing cycle through pipe 28 and pump 29 to device 18, from which the liquid is pumped" by pump 29 through pipe 30 to device 17, the Overflow from which runs as stated to the precipitator. A tank 32 for diluted barren solution is connected by pipe 33 to a pump 34 whose outlet pipe leads to the device 20, connected by piping 35 and pump 34 to device 19, and the overflow outlet pipe 35' of said device is connected with pump pipe 13 for said device leading back to the tank 32. l Q

rifhe regenerating apparatus comprises an electrolytic cell or cells 40 provided with a pervious diaphragm 4-1 dividing the cell into. anode and cathode compartments 42 and 43, containing respectively the anode 44 and cathode 45, connected to the wires 46 and 47 of an electric supply circuit. The anode compartment 42 is covered and is connected by pipe 50 to a suitable device such as tower 51 for introducing the chlorin into the leaching solution. The cathode compartment of the cell is. connected to suitable means, indicated at 53' for separating the sodium hydrate from thesodium chlorid.

Said means 53 may comprise an evaporating tank where the solution is evapora-ted to crystallize out the sodium chlorid, the sodium crystals being discharged into a brine tank 531 and the sodium hydrate being discharged into a tank 52. A tank 54 is provided for supplying sodium chlorid solution through pipe 54 to the cell 40, and this tank -may be supplied, in part, from the brine tank 53 through a pipe 56 and The leaching solution may be supplied to the absorption tower 51 by a pipe155 leading from a storage tank 57 for containing barren solution, the solution being pumped to said tank from the outlet pipe 27 of tank 25, byy a pump 58 connected by pipe 59 to the tank' 57. The outlet pipe 60 for regenerated solution leads from towerl to the agitator 1.

My process is carried out in the above described apparatus as follows: A concen trated solution of sodium chlorid, for ex.- amp'le, a saturated solution, is supplied to the cell 40 from tank 54, and is electrolyzed therein, producing sodium hydrate in the anode compartment, and free chlorin in the cathode compartment. The cathode solution containing sodium hydrate, together with sodium chlorid, is led through pipe 53 t'o the apparatus 53 in which it is evaporated so as to cause the sodium chlorid to crystallize out of the solution. The sodium hydrate solution is then passed to tank 52 for evaporation to formcaustic soda, and the sodium chlorid is passed to tank 53', wherein it is mixed with water to form a saturated solution of NaCl which is then pumped back to tank 54.` The free'chlorin passes from the` anode compartment through pipe 50 to tower 51 wherein it is absorbed into the so lution passing through the tower from tank 57. Said solution consists essentially of a solution of calcium chlorid in water .(say 5 to 10 per cent. strength), containing also from 6 to per cent. of iron as ferrous chlorid, the amount of iron being determined bythe nature of the ore. The action of the chlorin as it is absorbed into said solution oxidizes the ferrous chlorid to ferrie chlorid,-

' solution from the .as the leaching solution, thereby avoidlng excessive dilution of such solution. When the ore with the weak barren solution is delivered into the agitator 1, it is mixed with the strong regenerated barren solution supplied from tower 51, and itis subjected to the action of the ferrie chlorid and free chlorin in said regenerated solution, with the result that the copper vis, dissolved. The operation may be so controlled that a large portion of the copper in the final solution is present as cuprous copper, which is held in solution by reason of the calcium chlorid present, and the iron is reduced to ferrous chlorid, the solution of the copper being effected in part by the chlorin derived from the ferrie chlorid and also in part by the free chlorin. ,The resulting pregnant solution is drawn oft together with the nely divided ore through pipe `15 to the device 17 95. wherein it is displaced from the ore by barren solution supplied to device117 from de- I' vice 18 and to device 18 .from pipe 28 leading from tank 25, the effect of the two dis`\ placing'actions in devices 17 and 18 being 100 to substitute for the pregnant solution mixed with the ore, a barren solution' which may be discharged from the device 18 along' with the gangue without loss ofv copper. The pregnant solution\passes from device 17 105 through pipe 22 to the precipitator 23, where it is subjected to theaction of metallic iron, causing the copper to be precipitated and the barren solution then passes through pipe 24 to tank 25, whence a portion of such solu- 110 tion is passed through pipe 27, pump 58 and pipe 59 to the tank 57- for repetition of thel cycle. Another portion of the barren solution passes through the pipe 28 to the device 18 where it serves to displace the pregnant 115 ore or gangue as above described.

In working an ore containing a considerable amount of calcium carbonate or similar compound, the action of the chlorin' in 120 the leaching solution causes a certain amount of calcium chlorid to be taken up into the leaching solution. This calcium chlorid tends to accumulate in the solution in the cyclicoperation, and the process is so car-` ried out that the amount of calcium chlorid l taken up by the solution by the'action of the leaching agent on the calcium compound in the ore is just balanced by the loss of calcium chlorid. carried off with the Waste or tailings discharged at 21. In order to minimize the loss of chlorin the barren'solution resulting from the displacement of pregnant solution by barren solution in devices 17 and 18, is in turn replaced by 'a solution from the overflow of device 12, this last replacing solution being a dilute barren solution which contains considerably less percentage of calcomino` with the ore from device (3. sothat .12, through pipe 13 to tank 32, whence it is drawn by pipe 83 back to the ldevice 20. In the devices 20 and 19, this dilute calcium chlorid solution replaces the moderately strong solution coming from device 18, such` moderately strong solution passing by pipe back to the device 12, and the dilute solution being discharged along with the gangue, at 21, so that the only loss of chlorin to the cycle is thatdue to the small percentage of chlorin contained in this dilute solution.

As distinguished from the usual processes of copper leaching, my process as above described nses only the alnount of sodium chlorid which is required to supply the chlorin for solution of the copper, and no chlorin salt is required to be added. to the solution at any time to serve as a carrier for the cuprous copper. Furthermore, all the chlorin is supplied to thencyele. in active 'form, so that there is no waste due to supply of inert or carrier chlorin. lVIoreover, by

separating the sodium constituent. and replacing it. as far as necessary, by a base metal .(calcium) naturally present in the,

ore. I am enabled to'utilize such constituent.`

in the tailings, does not constitute any serious charge on the process. In the action of the chlorin 1n the leaching solution on the calcium compound present iny the ore, more or less hypochlorous acid may be formed. For example, by the action of the-ferrie chlorid on calcium 'carbonate, rferrie carbonateor hydrate may be formed, and inthe presence ot' free chlorin Such carbonate or'hydrate may be reconverted to 'ferrie chlorid. and at the same time free hypochlorous acid-will be produced. -The free chlorin is therefore' of advantage not only. in directly. acting 'on the ore, but also inffregenerating the chlorid of iron and in producing free hypochlorous acid, the lat-v ter being an effective leaching agent,` par-V ticularly when any of the copper is present as sulfid.

l-n'theI cycle above described the produc-y tion 'of calcilln'i ,chlorid by the action` of chlorin onthe calcium compound in the ore is inhibitedor reduced Vby reasonof the cal'- eium chlorid already t'ormed and in solution, and in so far as 'this inhibiting action takes place the presence ot'calcium.chloridv in solution will correspon `lingly reduce ythe loss "of chlorin in the cycle. ln starting the process calcnnn-chlorld or sodium chlorid may be supplied to' the solution'in sufficient amount to serve as a carrier for the cnprous copper, or, it' desired, such calcium chlorid may vbeaccumulated in the solution by the action of the leaching metal compound.

that I claim is: f y 1. The process ot' extracting a metal from an ore thereof, supplied together with water, which consists in displz'ieing sach water by a. solutionof an alkaline earth metal chlorin, introducing into such solution a metallic chlorid capable ot reduction to a lower chlorid` so as to leach the metal from the ore to torni a pregnant solution, replacing such'ln'egnant` solution by a barren solution, precipitating .the extracted metal from said pregnant solution to form such barren solution. and` replacing such barren solution from the ore by a dilute alkaline earth'metal solution prodiiced in the displacement of water Jfrom the ore by` alkaline earth metal chlorid solution, V l y n A2.*The process of extracting a metal fromits ores, whielreonsists in leaching the ore with asolution ernitaining chlorin in an active condition for solution of the. metal, and also'containing amehlorin compound acting` as a carrier forthe dissolved metal` with@ drawing the solution from the ore, plrecipitating said metal therefrom, regenerating a portion ofthe resulting barren solutionA for repetition ot thev process, and passing another portion of such barren solution into the ore coming Jfrom the leaching operation to displace the pregnant solution therefrom.

3. The process of extracting a metal from its ores, which consists i'n leaching the ore With a solution containing chlorin in active agent 'on the base y the -action of free clorin, for repetition ofthe process, displacing the barren solution from the ore by a more dilute barren solution, and passing the barren solution so fdisplaced into a fresh portion of ore, preparatory to leaching the same, to displace water from such fresh portion of ore and produce dilute barren solutionV for repetition of such displacing operation.

4. The process of extracting a metal from its ores containing a compound ofa base metal whose chlorid is capable of acting'as a carrier for a chlorid of the metal to be extracted, which consists in electrolyzing a concentrated solution of sodiumchlorid to produce free chlorin and sodium hydrate, separating such sodium hydrate as a byproduct, absorbing said chlorin in a solution .containing a metallic chlorid capable of oxidation to a higher chlorid, to produce a solution containing chlorin in active form, leaching lthe ore with such solution,.thereby dissolving as chlorid, the metal to be extracted, and also dissolving, as chlorid, a

portion of the base metal in the ore, forming a chlorid acting as a carrier for the metal to vbe extracted.

5. The process of extracting a metal from an ore thereof containing a base metal compound which consists in leaching such ore with a solution containing chlorin in active condition in such manner as to extract said' metal fromfthe ore and to react with 'such base metal compound to form a base metal chlorid capable of retaining thel extracted metal in solution, removing the resulting pregnant solution from the ore, repeating the operation in cyclic manner so as to ac-A cumulate such base metal clorid in the solution until the amount thereof so accumulated is suioient to 4act as a carrier 'for the extracted metal; and then continuing vsuch cyclic operation in such manner as to supply to the solution during each cycle, by the above stated reaction, an amount of base metal chlorid equal to the amount lost from `the cycle with the tailings. 6. The process of extracting a metal from an ore thereof'containing a base metal cornpound which Iconsists in leachin with a solution containing ferrie c lorid and free cilorin, in vsuch manner as to dissolve the metal to beextracted together with some Aof such base metal, as chlorids, the chlorin also serving to redissolve iron precipitated from sa id pregnant so barren-solution and replacing the barren sovthe ore.

from solution during the leaching operation by the action of the base metal compound and to form an active leaching compound containing oxygen and chlorin, withdrawing the resulting pregnant solution from the ore, precipitating the extracted metal` from the pregnantsolution, and regenerating the bar.- ren solution by supplying chlorin thereto, all in cyclic manner. A

7 The process of extracting a metal from an ore thereof containing a base metal compound, said ore beingsupplied together with water, `which consists in replacing such water with a barren solution, then supplyn ing to the ore a leaching agent containing ferrie chlorid land free chlorin so as to dissolve the metal to be extracted and some of the base metal as chloride, thechlorin also serving in part to redissolve iron precipitated from solution during the leaching operation by the action of the base metal compounds, withdrawing the resulting pregnant solution fromr the ore, replacing 'the remaining pregnant solution from the ore with barren solution, precipitating the' ex- 'tracted metal Ifrom the pregnant solution to form such barren solution, regenerating a portion `of such barren solution for cyclic repetition of the process, and replacing the barren solution in the tailings with the dilute barren solution resulting from the rst mentioned replacement wherein the water entering with the oreis replaced by; barren solution. Y f

8. rlhe'process of extracting a metal from its ores which consists in leaching the ore 'witha solution containing chlorin in active condition together with a chlorid capable of retaining the extractedI metal in solution,

displacing the resulting pregnant solution from the ore by barren solution, precipitating the :metal from said pregnant solution to formsuch barren solution and regenerating the'barren solution by the action of free 'chlorin for repetition of the process.

9. The process of extracting a metal from an ore thereof supplied, together with water, which consists in replacing such water with barren solution producing a dilute barren solution, supplying lto the ore and barren solution an active leaching agent,'replacing the resulting pregnant solutionwith barren solution, precipitating the extracted metal lution tol form the said ica lution in the tailings with dilute barren so- WALTER AUGUST senr/inout 

